Balance-wheel for time-pieces



(No Model.)

H. BI-LGRAM.

BALANCE WHEEL FOR TIME PIECES.

No. 455,787. Patented July 14, 1891.

INVE NTOR WITNESSES:

./w a. M. QZJflQ/M UNITED STATES PATENT OFFICE.

IIUGO BILGRAM, OF PHILADELPHIA, PENNSYLVANIA.

BALANCE-WHEEL FOR TIME-PIECES.

SPECIFICATION forming part of Letters Patent No. 455,787, dated July 14,1891.

Application filed May 24,1896- Serial No. 353,009. (No model.)

To all whom it may concern:

Be it known that I, HUGO BILGRAM, a citizen of the United States ofAmerica, residing at Philadelphia, in the county of Philadelphia andState of Pennsylvania, have invented certain new and useful Improvementsin Balance-VVheels for Clocks and lVatches, of which the following is aspecification, reference being had therein to the accompanying drawings.

My invention relates to the construction of a compensating balance-wheelfor clocks and watches; and it consists in a construction thereofhereinafter set forth, at once simple, cheap, and effective.

Referring to the accompanying drawings,

Figure l is a diagrammatic representation exemplifying the principle ofmy invention. Figs. 2, 3, 4, and 5 are forms of practical constructionof a balance-wheel according to this principle.

In all of these the spokes A of the wheel are of zinc or brass, or othermaterial more eXpa-nsible under increase of temperature than thematerial composing the rim, and the rim B is composed of steel or othermaterial less eXpansible under-increase of temperature than the materialcomposing the spokes.

Referring to Fig. I, the solid and dotted lines, respectively, indicatethe relative positions of the spokes and rim under lower and highertemperatures in highly exaggerated proportions. It will be observed thatupon expansion the sides of the rim between the spokes are drawn towardthe center, and that by a weight, as D, on the rim the effect of thismovementin reducing the momentum of gyration of the wh eel is enhanced,and it will also be observed that the greatest angular movement is at ornear the point marked a, and that an arm, as 0, connected to the rim atthis point will have a movement at its end much greater than the rim atthe corresponding point, and that a weight, as D, placed at the end ofthis arm will have a greater effect in equalizing the momentum ofgyration of the wheel under varying temperatures than if on the rim, andif of suflicient mass will reduce this momentum upon increase oftemperature.

Like letters represent like parts in Figs. 2, 3, 4i, and 5, whichrepresent some of the forms in which the principle may be applied. In

Fig. 2 the arms are placed without the rim. In Fig. 3 the arms areplaced within the rim. In Fig. at the arms are placed upon the rimsecured by rivets at a, and are furnished with a bar O, by which part ofthe weight of the arm is brought near the center. In Fig. 5 the arms areconnected at the j unction of the spokes and the rim and are of a curvesimilar to that of the rim, so that under expansion their points ofcontact change and the inward movement of the weights is enhanced in aprogressivelyinereasing ratio. The rim may be circular, or for greatereffect may be elliptical, as shown in Fig. 2, the angular movement, asat a, being greater in proportion to the eccentricity of the ellipse. EE are weights, which may be attached at the ends of the spokes tocounteract the effect of the weights D under changes of temperaturewhere it may be found necessary.

I claim as my invention 1. A balance-Wheel for clocks and watches,consisting of spokes of a material more expansible and a rim of amaterial less expansible under increase of temperature, said rim beingin length less than the circumference of a circle of which the distancebetween the ends of the spokes is the diameter.

2. A balance-wheel for clocks and watches, consisting of spokes of amaterial more expansible and a rim of a materialless expansible underincrease of temperature, and having weights connected to the rim betweenthe spokes by arms adapted upon expansion to give to the weights amovement greater than that of the corresponding part of the rim.

A balance-wheel for clocks and watches, consisting of spokes of amaterial more expansible and a rim of a material less expansible underincrease of temperature, and having weights connected to the rim betweenthe spokes by arms adapted upon expansion to give to the weights amovement greater than that of the corresponding part of the rim in aprogressively-increasing ratio.-

In testimony whereof I have affixed my signature in presence of twowitnesses.

HUGO BIL #RAM. Witnesses:

G. MORGAN ELDRIDGE, GEORGE E. HOUSE.

